This study is designed to follow prospectively a relatively segment of a population of men over an extended period of time and to record the rate of change of signs, symptoms and selected physiologic measurements associated with the development of chronic non-specific respiratory disease. In addition, determination of the prevalence and relative importance of hypertension and other significant cardiovascular disease in this population is under investigation. Intense exposure to automobile exhaust and cigarette smoking are the major environmental factors under consideration. Fixed location sampling at 16 traffic intersections and in police automobiles during the previous two years have provided extensive information on SO2, NO2, Co, total hydrocarbons, total and mass respirable dust, and lead in air. Personal lapel monitoring are now being conducted for all these contaminants except SO2 and total hydrocarbons. thus far, over the last four years, minimal excessive decline in pulmonary function in men witht th highest exposure levels have been identified. Further follow up in groups of men with varied and monitered exposure are being vonducted.